Mechanical roasting-furnace.



APPLICATION FIXED MAY 22, |914.

Patented Jan.2,1917.

4 SHEETS-SHEET 2 W. SCHEFCZIK. MECHAMCAL RoAsTING FURNACE. APPLICATION FILED MAY 22| |914.

4 SHEETS-SHEET 3.

Patented Jan. 2, 1917.`

W. SOHEFCZIK.

MECHANICAL ROASITING FURNACE. APPucAlon FILED 4M/22.1914.

Patented J an. 2, 1917.

WILHELM SCHEFCZIK, 0F HAMBORN-ON-THE-RHINE, GERMANY.

MECHANICAL ROASTING-FURNACE.

Specification of Letters Patent.

Patented J an. 2, 1917.

Application led May 22, 1914. Serial No. 840,246.

To alli/17mm it may concern:

Be it known that I. WILHELM SCHEFCZIK, a subject of the German Emperor, residing at the city of Hanlborn-on-the-Rhine, in the Kingdom ot' Prussia, Germany, have invented certain new and useful Improvements in Mechanical Roasting-Furnaces, of which the following is a specification.

This invention relates to mechanical roasting furnaces comprising stationary mailles having curved bottoms, and the prilnary object 1s to provide improved means for conveying the material along the inside of the inutiles.

Another object is to provide an improved conveyor for charging the muflies.

A further object is to provide improved means for driving the conveyer means in the mames. i

Another object is to provide an improved bunker forsupplying material to the con veyer.

Other objects of the invention are described hereinafter.

To these ends. the invention consists in the construction. arrangement and combination of parts described hereinafter and pointed out in the claims.

One illustrative embodiment of the invention is diagrammatically represented by way of example in the accompanying drawings. wherein Figure l is a longitudinal section of one form of my mechanical roasting furnace, taken on the line A-B-C'D of Fig. 2.- Fig. 2 is a vertical transverse section of the same. Fig. 3 is a detail View of conveyer teeth. Fig. 4 is a vertical elevation showing an improved bunker for charging the furnace. and Fig. 5 is a diagrammatic end elevation of means for driving the conveyers in the mufiies. l

Referring to the drawings, in the form shown in Figs. Vl and 2 three mailles a, each having.r approximately the form of half a cylinder are arranged with the round side downward one above another, and a second system comprising three similar inutiles is arranged laterally thereof. so that in this ease the furnace comprises 4six mailles. If

preferred. each inutile may be formed as a complete cylinder. Below each tier of three muflles o l have provided a furnace 1() from which lead pairs of serpentine heating fines having a section 11. extending from the fur4 une :wie: die bottoni of the hover mattie cal flue 14 at the front.` to the upper flue section 15 that terminates in a vertical Hue 1G leading to the stack.

Arranged within theinasonry of the furnace at each side thereof are separate similar serpentine air admission fines l?, Fig. 2, each having a branch 18 to admit heated air above the grate of the furnace and a branch 19 to admit heated air below said grate. These filles may be controlled by dampers, as is customary (not shown) or these dampers may be omitted. Between the two tiers of inutiles c arranged in a. vertical plane. is a third serpentine air passage 20 having lateral. extensions 21, that admits heated air into the front end of the upper mufllcs o.; 22 that admits air to the furnace flue section l5; that admits air to the rear of the second or middle inutiles of the tiers; 2i thrit admits air to the rear end of the tiuc section 13, and 25 that admits air to the front end of the lower inutile. This air also becomes heated in passing through the masonry to its Several points of discharge.

The gases from the inutiles arising from the roasting operation. and especially where sulfur is evolved from thc ore treated. pass from the lower muflle a at its rear end, up to the next maille, through the chute 26 to the middle inutile. through the latter to its front end, thence through the chute 27 at the front of the upper inutile. and are discharged through openings 28, Fig. 2. in the upper part of the rear end of said Inutile to a separate stack 29. or pipe. for conveyance to a sulfuric acid plant.

All the inutiles are fixedly mounted, that is to say, formed in or builtin as a part of the masonry, and are not. as is usually the case, separate, removable fire-clay elements.

Each. inutile has a horizontally journaled hollow shaft L. on each of which` are two or more vertical arms c which carry a. rabbling member. c. g. a channel-iron or bar, located parallel with the shaft, on which bar or channel are provided exchangeable teeth r for mixing and conveying the ma terial to be roasted; IThen the muflles have only a round bottom, thus for example when the inutiles are semicylindrical, there are two or more rows of teeth.` the teeth of one row offset from those of the adjacent row. These teeth are isosceies triangles in plan view with the points Il' directed toward the front (Fig. 3) or toward the direction in which the material is to move. When two rows of teeth are provided thil individual triangular' prisms are arranged displaced relatively to one another, in order that the material to be roasted which is pushed by the sides of the triangles toward the point and passes this point laterally arrives on to the inclined plane which is formed by a Side of the adjacent triangle and is thus pushed onward in the same direction. even when the teeth have imparted to them a. reciprocatory motion. Fast on one end of each hollow shaft outside the muflles is a gear-Wheel e driven by a vertically reciprocated toothed rack f or the like. so that the shafts and all the stirrers have imparted to them an os cillatory motion. their teeth (l being driven to and fro over the curved bottoms of the muflies, so that the material to be roasted is fed forward while it is moved laterally on the curved bottoms of the mnffles but mainly forward by the slanting faces of the teeth. There must be at least two rows of these teeth (I displaced relatively to one another, otherwise the material to be roasted would remain stationary in the space between the apex of one triangle and the base of the triangle in front. It will therefore be. readily understood that another arrangement is possible.

On the one end of the furnace away from the charging inlet of the top muffle is provided an ore bunker. from which the 11ndried crude ore falls into a scraping belt or push conveyor o F ig. 1l, conveyer worm or the like; the latter conveys the ore slowly along the top of the furnace toward the inlet at the other end of the same` whereby it is gradually dried by contact with the hot roof of the furnace.

An iron hopper 30 (Fig. 1) is provided on the top at the one end of the top mufllc. into which projects a solid rotating cone h having teeth milled therein, its periphery being somewhat steeper than that of the iron hopper. The cone can be raised and lowered by the spindle i'. The spindle i is rotated by a. suitable gear train and is adjustable. For this purpose it is slidable through a bevel pinion 31 that gears with a bevel wheel 32 on a. horizontal shaft 33 carrying a pinion 34 that is actuated hy a sector 35 secured on the upper hollow muflle shaft I), there being one such feeding device for each tier of lnuflles. lt will thus be seen that the Conc la. acts to break up the lumps, and that the feed will be proportionate to and dependent upon the speed of movement of the shaft b; in `other words, proportionate to the rate of movement of the ore through the muffie. lVhen the roue is in its lowest position it contacts with the bottom of the hopper in consequence of the difference in slant of the sides of the two. The cone is lifted depending on the quantity of ore to be charged until the opening is sufficiently wide, but is nevertheless only so wide that the lower part of the hopper remains filled with ore so that no gas can escape from the furnace. In the furnace itself the ore travels forward longitudinally in the upper inutile from the inlet to the chute 2T, drops therethrough into the middle muflie, sliding down slantwise through the hopper or chute without producing dust into the next lower muffle. and so on and is discharged fronithe lower muflle through passage 36.

The furnace gases under the inutiles are conducted opposite to the. direction of inotion of the ore in order, in combination with the heat of combustion of the material to be roasted and with a supply of preheated regulatable quantities of air for each muffle through branch passages 21, Q3 and 95, to accelerate the roasting process. The furnace which is heated by gas or coal can be regulated by supplying preheated regulatable quantities'of air above a'nd below the f grate by air flue 17 and its branches 18 and 19. and in addition preheated air can be supplied in regulatable quantities to each heating flue by fines 2Q, 23 and 24, so that the total combustion can be increased and damped, and also the distribution of heat inthe furnace itself and the drawing of the flame almost up to the flue can be regulated. If gas firing is to be used, when the furnace comprises mufiies arranged one over another with intermediate heating flues one or more burners 37 is or are introduced into each heating flue or fines. l

The ore bunker (Fig. 4) likewise has an Aimproved construction. lts angle of slant may he adjusted and also its spout corresponding to the ease with which the different ores slide down` so that the quantity of ore supplied can be regulated, and such materials as* slide only with difficulty owing to being wet for example can be charged into the furnace. (living td the bunker l: itself and its lip or spout l being adjustable independently one of the other it is possible exactly to adjust the supply of the material. This is aided by the provision of a roller lm, or the like `ovhich rotates Abhetween the bunker 7c and the spoilt Z, its object being to keep the niaterihlsliding uniformly and to crush lumps, e. in wet ores.

A gate fn` arranged to'move up and down in front of the roller affords another possibility of regulating the supply of the material and preventing too much falling on the roller and obstructing the latter. The gate n is raised and lowered by a screw -lO and hand wheel il supported in a` standard lf2 on the chute la, the gate sliding in vertical guides 43on the sides of the chute or bunker. The lateral guides of this gate are not confmwa to the bottom of the bunker in order to prevent the guides being stopped up. Fig. 4 shows a slde elevation of the bunker; 0 is a floor-frame for carrying the shaft p on which the bunker l: proper and the spout l are rotatably mounted. Both are suspended from rods r, 8 which can be shortened by nuts or turn buckles 8.and`t having right and left-handed threads; in this manner it is possible to adjust the slant of the bunker It' and its spout or lip l exactly and to change from one inclination lto another.

A roller m is mounted at the outlet of the bunker; this roller feeds the material on the one hand, and, on the other hand, when it is necessary, disintegrates it by means of teeth or the like thereon.

The above-described furnace could be driven by means of a motor and transmission gearing; the same is, however, driven much more advantageously with the hydraulic means described hereinafter with reference to Fig. 5. The stirring`mechanisms of all mechanical furnaces require to be driven slowly. They therefore require a large ratio of transmission by means of belting or the like in consequence of the high speed of the electric motors. This kind of drive frequently requires considerable space and entails great loss of energy owing to friction. The most important defect of the said drive, however, is that it is possible to regulate the speed of the stirring mechanism only very imperfectly by means of stepped pulleys'and series resistances for the motor. Particularly when roasting zincblendes materials have to be dealt with which on the one hand require thorough roasting and on the other hand are of such various natures that only an apparatus capable of regulation Within wider limits than those known heretofore can yield economical results with all kinds of ores. Reference may be made merely to the differences in zincblendes in size of grain, hardness, percentage of sulphur and zinc, admixtures of troublesome gangues and` metals, and in changing influences exercised by the many processes of enrichment and treatment. These greatly changing conditions can be met only by a. furnace whose stirring mechanism can have its speed regulated Within wide limits and thereby causes the material to be roasted toremain in the furnace for a time adapted to the kind of ore in question. These conditions are met by the apparatus described hereinafter.A

As shown in Fig. '5, gear-Wheels e are keyed on the ends of the shafts b which are located horizontally in` the longitudinal muies a, and which carry arms c, having conveyor teeth of for the material t0 be roasted.` These gear-*wheels are oscillated by a frame comprising a toothed rack f or,

plied above and below the piston the lattery 1s driven' down and up and drives the driving mechanismy and with it the stirrers in the described manner. In order to automatically reverse the direction of flow of the water under pressure at the desired moment the following 'reversing device fis provided.

Attached` to the piston-rod u is a connectingrod which rotates a cone or plug valve a ina suitable casing or box by means of the crank y. This cone z ha's two recesses 1 and 2 of semicircular section inopposite sides thereof. Assuming that Water under pressure flows into the recess 1 through the pipe 3, it can flow without obstruction into the pipe 4 and arrive above the piston o which it will drive downward, The Water on the opposite side of the piston can flow through the pipe 5 into therecess 2 and can esca-pe through the pipe 6., In consequence of the connection of the cone z by means of the connecting rod and the crank with the iston Yv, when the latter moves the cone z 1s also rotated until the recess 1 is connected with the pipes 7 and 8 and the recess 2 is connected with the delivery pipes 9 and 6; the piston andstirrcrs are thereby driven in the opposite direction While the pipes 3, 4, 5 and 6 are closed by the cone.

For passing over the dead point the reversing device is connected in such manner with the. frame and stirrers that at the moment of reversal the frame and stirrers continue to fall a short distance and rotate the cone a little farther. In order that the water under the piston shall not Aprevent this fall the supply and delivery pipes are displaced at the casing or box relatively to one another an amount equal to their diameter so that the rotating cone first releases the delivery pipes and then the supplypipes of the opposite side, so that the outflow of thewatery begins first and the Water under pressure ows in a moment later .to y the other side of the piston. By properly adjusting the cock or valve 45 in the discharge pipeprovision is made that the water which has done its work does not escape too rapidly and, as it vwere,`constitutes a cushion in order to assure uniform motio-n of the pump piston. The valve 44 in the inlet pipe controls the water admitted. The advantages of the hereindescribed invention may be summarized as follows The hydraulic driving device and the frame and stirring loo mechanism occupy very little space outside pairs thereto are. in 11o-way obstructefli. The speed of the stirrers can be regulated rjyhin very wide limits by one single manip rtion by simply regulating the waiter supp y hy one cock. ner unattained heretofore to the yarious ma terials and conditions of working. The piston and stirrers can be stopped in any position and w ithin the fraction of a second by closing cocks, which may frequently preserve the entire gearing from fracture when disturbances occur. In consequence of the simplicity unknown heretofore injury of the driving mechanism is almost impossible' as all cams, balancers, springs and the. likesuch as are comprised in \\ate1'colunin inarhines, are aroided.

l. In a mullle furnace, the combination with a round bottom maille; oi' a hollow .shall mounted longitudinally therein, a single rabbling member parallel with said shaft. a single series ot' arms connecting said member and shaft. a plurality ofrows of triangular teeth rigidly secured to saidmember, the teeth of one row off-set from the teeth of its adjz'lcent row, and means to oseillate said shaft.

L. 1n a mutlle furnace, the combination with a series of superposed mutllechambers discharging by gravity through openings in their bottoms into one another; of an oscillating rabbling mechanism in each mullle comprising,r a Shaft passing longitudinally through the rouille. and a toothed rabbling member supported by the shaft, a feeding device for the upper Inutile cornprising' a hopper and a eoperating cone and means to rotate said cone from the Shaft of a Inutile.

3. In .i` mufflel furnace, the combination with a maille thereof; of a shaft extending longitudinally through the mnflle, a rabbling member secured to said shaftI and having thereon a plurality of rows of triangular teeth, a hopper discharging-into the maille, a cone cooperating with said hopper, a'gear train between Said shaft and cone and means for oscillating said shaft.

4. In a, inutile furnace, the combination with superposed, non-removable mailles, fire fines arranged only under the soles of said inutiles, means to introduce air to said flues when desired, and means to separately heat said flues when desired, and a furnace -for successively heating all the fire flues of a superposed series of mailles.

5. In a maille furnace, a shaft 1n each Copie; ot this patent may be'obtained for ve cents eanh, by addressing the "Gommissioner of Patenti.4

It can be adapted in a man- Y .water to and from said piston, and means to regulate tht` low of water to and from said cylinder whereby the speed of said piston and rabble may be instantly changed at (i. In. a mechanical roasting furnace, the. combination of a plurality of stationary mullles arranged one over another in groups, oscillatory mixing and conrejifingn'ieauscomprsing a horizontal shaft in each Inutile. a gear wheel fast on the end of each Shaft outside the mullles` a frame comprising toothed racks meshing with .said gear wheels` and hydraulic means for reciprocating said frame.

T. ln a mechanical roasting furnace, the combination ol' a plurality of stationary muflles arranged one over another in groups, oscillatory mixing and conveying means comprising a horizontal .shaft in each mullle, a gear wheel fast on the end of each shaft outside the inutiles. a frame comprising toothed racks meshing with said gear wheels and hyd aulic means comprising a pump having a piston-rod connected to said frame, supply and delivery pipes connected to the two ends of the pump, and reversing means comprising a box connected in said pipes and a plug haring recesses movable in said box.

S. In a mechanical roastingr furnace, the combination of a. plurality of stationary inutiles arranged one over another in groups, oscillatory mixing and conveying means comprising a horizontal shaft in each Inutile, a gear wheel fast on the end of each shaft outside the mailles, and a frame comprising toothed racks meshing with said gear wheels, and hydraulic means for reciprocating said frame; said hydraulic means c0rnprising a pump having a piston rod connected with said frame, supply and delivery pipes connected to the two ends of the pump, and reversing means comprising a box connected in said pipes, a plug,lr having recesses rotatable in said box, and means for rotating said plug connected to said piston rod.

In testimony whereof I affix my signature in presence of two witnesses.

WILHELM SCHEFCZIK. [Ls] lVitnesses HELEN NUFER, FRANCES NUFER.

Washington, D. C. A 

